1. Field of the Invention
The present invention relates to a steering damper.
Priority is claimed on Japanese Patent Application No. 2003-151263, filed May 28, 2003, the content of which is incorporated herein by reference.
2. Description of the Related Art
As a steering damper included in steering systems of vehicles such as conventional motorcycles, a type of steering damper is known, which controls damping force generated in the steering system by controlling a pressure control valve provided in a fluid path of a steering damper body so as to change damping force generated by the pressure control valve (for example, refer to Japanese Examined Patent Application, Second Publication No. H7-74023).
The conventional steering damper mentioned above has problems described below.
In the conventional steering damper, a load applied to a front wheel of a vehicle is measured, and electrical current supplied to a solenoid that is installed in a pressure control valve is controlled so as to increase a damping force when the load is decreased. Because the relationship between a steering angular velocity and the damping force of the steering system is set to be basically linear, when the steering damper is configured so that an operation force at the steering handle at the beginning of a steering operation is set to be low, the vibrations due to road surface disturbances in a low steering angular velocity region during high speed driving cannot be absorbed. In contrast, when the steering damper is configured so as to absorb the vibrations due to road surface disturbances in a low steering angular velocity region during high speed driving, the operation force at the steering handle at the beginning of a steering operation becomes high.
In other words, in the conventional steering damper, it is not possible to simultaneously achieve two objects, i.e., one is to set the operation force at the steering handle at the beginning of a steering operation to be low, and the other is to absorb the vibrations due to road surface disturbances in a low steering angular velocity region during high speed driving.